# Omiros Ragos

Omiros Ragos | |
---|---|

Omiros Ragos | |

Residence | GR-26500 Patras, Greece |

Nationality | Greek |

Scientific career | |

Fields | Professor of Mathematics |

**Education** * 1989 : Ph.D. in Mathematics, Department of Mathematics, University of Patras, Greece

- 1982 : Diploma in Mathematics, Department of Mathematics, University of Patras, Greece

**Academic positions** * 2006- : Senior Assistant Professor, Department of Mathematics, University of Patras, Greece

- 2001-2005 : Assistant Professor, Department of Mathematics, University of Patras, Greece
- 1996-2001 : Lecturer, Department of Mathematics, University of Patras, Greece

**Research Interests** * Computational methods in dynamical systems, Numerical solution of non-linear and differential equations.

**Teaching** * Programming Languages, Logic Programming, General Mathematics

**Publications in International Journals** # O. Ragos and C. Zagouras, The zero velocity surfaces in the photogravitational restricted three-body problem, 1988, Earth, Moon, and Planets, 41, pp.257-278.

- O. Ragos and C. Zagouras, Periodic solutions about the `out of plane' equilibrium points in the photogravitational restricted three-body problem, 1988, Celestial Mechanics, 44, pp.135-154.
- O. Ragos and C. Zagouras, Periodic solutions around the collinear Lagrangian points in the photogravitational restricted three-body problem: Sun-Jupiter case, 1991, Celestial Mechanics, 50, pp.325-347.
- O. Ragos, C.G. Zagouras and E. Perdios, Periodic motion around stable collinear equilibrium point in the photogravitational restricted problem of three bodies, 1991, Astrophysics and Space Science, 182, pp.313-336.
- E. Perdios, C.G. Zagouras and O. Ragos, Three-dimensional bifurcations of periodic solutions around the triangular equilibrium points of the restricted three-body problem, 1991, Celestial Mechanics and Dynamical Astronomy, 51, pp.349-362.
- O. Ragos and C.G. Zagouras, On the existence of the `out of plane' equilibrium points in the photogravitational restricted three-body problem, 1993, Astrophysics and Space Science, 209, pp.267-271.
- O. Ragos and F.A. Zafiropoulos, A numerical study of the influence of the Poynting-Robertson effect on the equilibrium points of the photogravitational restricted three-body problem I. Coplanar case, 1995, Astronony and Astrophysics, 300, pp.568-578.
- O. Ragos and F.A. Zafiropoulos and M.N. Vrahatis, A numerical study of the influence of the Poynting-Robertson effect on the equilibrium points of the photogravitational restricted three-body problem: II. Out of plane case, 1995, Astronony and Astrophysics, 300, pp.579-590.
- M.N. Vrahatis, O. Ragos, T. Skiniotis, F.A. Zafiropoulos and T.N. Grapsa, RFSFNS: A portable package for the numerical determination of the number and the calculation of roots of Bessel functions, 1995, Computer Physics Communications, 92, pp.252-266.
- L. Drossos, O. Ragos, M.N. Vrahatis and T. Bountis, Method for computing long periodic orbits of dynamical systems, 1995, Physical Review E, 53(1), pp.1206-1211.
- M.N. Vrahatis, O. Ragos, F.A. Zafiropoulos and T.N. Grapsa, Locating and computing zeros of Airy functions, 1996, Zeitschrift f\\"ur Angewandte Mathematik und Mechanik, 76, pp.419-422.
- C.G. Zagouras, E. Perdios and O. Ragos, New kinds of asymmetric periodic orbits in the restricted three-body problem, 1996, Astrophysics and Space Science, 240, pp.273-293.
- M.N. Vrahatis, T.N. Grapsa, O. Ragos and F.A. Zafiropoulos, On the localization and computation of zeros of Bessel functions, 1997, Zeitschrift fur Angewandte Mathematik und Mechanik, 77(6), pp.467-475.
- M.N. Vrahatis, O. Ragos, T. Skiniotis, F.A. Zafiropoulos and T.N. Grapsa, The topological degree theory for the localization and computation of complex zeros of Bessel functions, 1997, Numerical Functional Analysis and Optimization, 18(1\\&2), pp.227-234.
- O. Ragos, K.E. Papadakis and C.G. Zagouras, Stability regions and quasi-periodic motion in the vicinity of triangular equilibrium points, 1997, Celestial Mechanics and Dynamical Astronomy, 67, pp.251-274.
- P. Kravanja, O. Ragos, M.N. Vrahatis, and F.A. Zafiropoulos, ZEBEC: A mathematical software package for computing zeros of Bessel functions of real order and complex argument, 1998, Computer Physics Communications, 113, pp.220-238.
- P. Kravanja, M. Van Barel, O. Ragos, M.N. Vrahatis, and F.A. Zafiropoulos, ZEAL: A mathematical software package for computing zeros of analytic functions, 2000, Computer Physics Communications, 124, pp.212-232.
- V.S. Kalantonis, E.A. Perdios, A.E. Perdiou, O. Ragos, and M.N. Vrahatis, On the application of optimization methods to the determination of members of families of periodic solutions, 2003, Astrophysics and Space Science, 288(4), pp.581-590.
- V.S. Kalantonis, E.A. Perdios, A.E. Perdiou, O. Ragos, and M.N. Vrahatis, Deflation techniques for the determination of periodic solutions of a certain period, 2003, Astrophysics and Space Science, 288(4), pp.591-599.
- E.A. Perdios and O. Ragos, Asymptotic and periodic motion around collinear equlibria in the Chermnykh's problem. 2004, Astronony and Astrophysics, 414, pp.361-371.
- V.S. Kalantonis, E.A. Perdios and O. Ragos, Asymptotic and periodic orbits around L_3 in the photogravitational restricted three-body problem, 2006, Astrophysics and Space Science, 301, pp.157-165.
- K. Papadakis, O. Ragos and C. Litzerinos, Asymmetric periodic orbits in the photogravitational Copenhagen problem, 2009, Journal of Computational and Applied Mathematics, 227 pp.102-114.

**Publiations in Conference Proceedings** # O. Ragos, M.N. Vrahatis and F.A. Zafiropoulos, The topological degree for the computation of the total number of equilibrium points in ODEs, 1995, 3rd International Colloquium on Numerical Analysis Invited Lectures and Short Communications (1994, Plovdiv, Bulgaria), edited by D. Bainov and A. Dishliev, Sc. Cult. Techn. Publ., Singapore, pp.147-156.

- O. Ragos and C.G. Zagouras, A numerical algorithm for the determination of regions of quasi-periodic motion in two-dimensional Hamiltonian systems, 1995, 3rd International Colloquium on Numerical Analysis: Invited Lectures and Short Communications (1994, Plovdiv, Bulgaria), edited by D. Bainov and A. Dishliev, Sc. Cult. Techn. Publ., Singapore, pp.157-164.
- O. Ragos, M.N. Vrahatis and F.A. Zafiropoulos, The topological degree for the computation of the exact number of equilibrium points of dynamical systems, 1994, Proceedings of the 2nd Hellenic-European Conference on Mathematics and Informatics HERMIS 94, Athens, Greece, Vol.2, pp.533-542.
- O. Ragos, M.N. Vrahatis and G.S. Androulakis, Methods for the computation of periodic solutions of dynamical systems, 1996, Proceedings of the Sixth International Colloquium on Differential Equations (1995, Plovdiv, Bulgaria), edited by D. Bainov, VSP, Netherlands, pp.213-220.
- O. Ragos, M.N. Vrahatis and F.A. Zafiropoulos, The computation of equilibrium points of up-to-three dimensional dynamical systems using the topological degree theory, 1996, Proceedings of the Sixth International Colloquium on Differential Equations (1995, Plovdiv, Bulgaria), edited by D. Bainov, VSP, Netherlands, pp.221-228.
- F.A. Zafiropoulos, T.N. Grapsa, O. Ragos and M.N. Vrahatis, On the computation of zeros of Bessel and Bessel-related functions, 1996, Proceedings of the Sixth International Colloquium on DifferentialEquations (1995, Plovdiv, Bulgaria), edited by D. Bainov, VSP, Netherlands, pp.409-417.
- F.A. Zafiropoulos, O. Ragos and M.N. Vrahatis, Linearized viscoelastic wave propagation, 1996, Proceedings of the Sixth International Colloquium on Differential Equations (1995, Plovdiv, Bulgaria), edited by D. Bainov, VSP, Netherlands, pp.417-423.
- M.N. Vrahatis, O. Ragos and G.S. Androulakis, A method for computing families of periodic orbits based on unconstrained oprimization, 1999, Proceedings of the NATO Advanced Study Institute on Hamiltonian Systems with Three or More Degrees of Freedom (1995, S'Agaro, Spain), edited by C. Simo, NATO ASI Series, Series C, Vol.533, Kluwer Academic Publishers, Netherlands, pp.642-645.
- M.N. Vrahatis, O. Ragos, F.A. Zafiropoulos and E.C. Triantafyllou, On the computation of all the equilibrium points in Hamiltonian Systems with three degrees of freedom, 1999, Proceedings of the NATO Advanced Study Institute on Hamiltonian Systems with Three or More Degrees of Freedom (1995, S'Agaro, Spain), edited by C. Simo, NATO ASI Series, Series C, Vol.533, Kluwer Academic Publishers, Netherlands, pp.638-641.
- O. Ragos, E.A. Perdios, V.S. Kalantonis and M.N. Vrahatis, On the equilibrium points of the relativistic restricted three-body problem, 2001, Nonlinear Analysis, 47(5), pp.3413-3418. Proceedings of the Third World Congress of Nonlinear Analysts (2000, Catania, Italy), edited by V. Lakshmikantham.
- E.A. Perdios, O. Ragos, A.E. Perdiou and M.N. Vrahatis, Symmetric doubly asymptotic orbits in the photogravitational restricted three-body problem, 2001, Nonlinear Analysis, 47(5), pp.3443-3448. Proceedings of the Third World Congress of Nonlinear Analysts (2000, Catania, Italy), edited by V. Lakshmikantham.
- M.N. Vrahatis, O. Ragos and G.S. Androulakis, Computing families of periodic orbits through optimization methods, 2001, Nonlinear Analysis, 47(5), pp.3449-3454. Proceedings of the Third World Congress of Nonlinear Analysts (2000, Catania, Italy), edited by V. Lakshmikantham.

## Abstracts

- 2012 - "Radar Signal Delay in the Dvali-Gabadadze-Porrati Gravity" (Read in full)
- 2011 - "[[Calculation of Radar Signal Delays in the Vicinity of the Sun due to the Contribution of a Yukawa Correction Term in the Gravitational Potential

]]"

- 2011 - "Eccentricity Functions in the Higher Degree and Order Sectorial Gravitational Harmonic Coefficients" (Read in full)
- 2010 - "Gauss' Planetary Equations in a Non-Singular Potential" (Read in full)
- 2010 - "Yukawa-type Effects in Satellites Dynamics"
- 2010 - "Yukawa-Type Potential Effects in the Anomalistic Period of Celestial Bodies"